The Male Peripubertal Phase as a Developmental Window for Reproductive Toxicology Studies

Abstract

The normal development of the male reproductive system can be divided into five phases: fetal, neonatal, childhood, puberty and adulthood. Childhood/peripuberty has yet been relatively little studied. Chemical insults during the peripubertal phase may result in adverse consequences that may be already visible during puberty as well as during later adult life. This occurs because endocrine disruptors often interfere in the developmental programming. The most important is to note that children are not just little adults and should be particularly investigated. The aim of this review is to discuss the recent literature (2000-2013) on male reproductive aspects in prepubertal toxicity assays, focusing on experimental in vivo studies, establishing a comparative analysis between the design, endpoints, results and consequent conclusion. The studies discussed in the present review were selected based on the period of exposure. Only studies with post-lactational exposures were included. 33 papers were included using rats, mice, rabbits or pigs as experimental model. There is a relative scarcity of studies investigating animals in development and thus an urgent need for further studies in order to evaluate the possible persistent effects on fertility and other reproductive parameters at adulthood. Another point is the lack of studies with chemical mixtures, an imminent problem in modern society. It is vital to consider the refinement of alternative methods and the experimental designs and endpoints to improve the scientific knowledge in this area.

Prepubertal exposure to low doses of sodium arsenite impairs spermatogenesis and epididymal histophysiology in rats

“…Pre‐ and peri‐puberty periods are considered critical phases of postnatal development, being the first life stage when the organisms will experience direct exposure to the contaminants, without the mediation of maternal metabolism. In addition, it is a period of endocrine, immune and morphological development . The spermatogenesis and steroidogenesis have not been completely established, making the organism more vulnerable to endocrine disruption caused by toxic agents .…”

Ethanol exposure during peripubertal period increases the mast cell number and impairs meiotic and spermatic parameters in adult male rats

“…Our techniques have been important in detecting alterations from ethanol exposure. Chemical insults during the peripubertal phase may result in adverse consequences that may be visible as of puberty, and may continue into later adult life (Perobelli, 2014). However, the effect of chronic consumption of average doses of ethanol during peripuberty, on the male reproductive tract of mammals, is unclear.…”

Fish pollutants MeHg and Aroclor cause permanent structural damage in male gonads and kidneys after prepubertal exposure

“…Puberty is a complex biological process regulated by the endocrine system, but the factors involved in this modulation are still poorly understood (Maranghi & Mantovani 2012;Perobelli 2014). In addition, special attention is given to neurobehavioral endpoints and exposure during adulthood or prenatal and lactation life.…”

“…In this context, there is a scarcity of studies investigating reproductive aspects after exposure to MeHg and PCBs associated, especially in models of exposure during pre-and peripuberty. Puberty is a complex biological process regulated by the endocrine system, but the factors involved in this modulation are still poorly understood (Maranghi & Mantovani 2012;Perobelli 2014). Exposure to chemicals during childhood deserves special attention, because at this stage the individual is, for the first time, in contact with environmental contaminants without the mediation of maternal metabolism as occurs during pregnancy and lactation.…”